Hair children don't seem to respond to changes?
Particle systems still seem to be a little buggy sometimes. I recently had a similar problem. The way to &quot;fix&quot; this is to press G to move the object and then hit ESC or rightclick to cancel the transform. That way it snaps back to its position before and the particles update. While this might be a possible workaround, there might be a better solution because obiously an instant update would be a lot more convenient.